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<a NAME="compare"></a>gm compare
</font></font></font></b></td></tr></table>
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<a NAME="comp-top"></a>NAME
</font></font></font></b></td></tr></table>
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compare - compare two images.
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<a NAME="comp-contents"></a>Contents
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<dl>
<dt>
<a href="#comp-syno">Synopsis</a>
</dt>
<dt>
<a href="#comp-desc">Description</a>
</dt>
<dt>
<a href="#comp-exam">Examples</a>
</dt>
<dt>
<a href="#comp-opti">Options</a>
</dt>
</dl>
</td></tr></table>
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<a NAME="comp-syno"></a>Synopsis
</font></font></font></b></td></tr></table>
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<p>
<strong>gm compare</strong> <strong>[</strong> <em>options</em> <strong>... ]</strong> <em>reference-image</em>
<strong>[</strong> <em>options</em> <strong>... ]</strong> <em>compare-image</em>
<strong>[</strong> <em>options</em> <strong>... ]</strong>
</td></tr></table>
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color="#00B04F"><font size="+1">
<a NAME="comp-desc"></a>Description
</font></font></font></b></td></tr></table>
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<p>
<strong>compare</strong> compares two similar images using a specified statistical
method (see <strong>-metric</strong>) and/or by writing a difference image
(<strong>-file</strong>), with the altered pixels annotated using a specified
method (see <strong>-highlight-style</strong>) and color (see
<strong>-highlight-color</strong>). <p><em>Reference-image</em> is the original
image and <em>compare-image</em> is the (possibly) altered version, which
should have the same dimensions as <em>reference-image</em>.
</td></tr></table>
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SRC="images/right_triangle.png"  ALT=">" BORDER=0 
height=14 width=15><b><font face="Helvetica, Arial"><font 
color="#00B04F"><font size="+1">
<a NAME="comp-exam"></a>Examples
</font></font></font></b></td></tr></table>
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<p>
To compare two images using Mean Square Error (MSE) statistical analysis
use:
<pre>
    compare -metric mse original.miff compare.miff
</pre>
<p>
To create an annotated difference image use:
<pre>
    compare -highlight-style assign -highlight-color purple -file diff.miff original.miff compare.miff
</pre>
</td></tr></table>
     <p>
<i><a href="#top">Back to Contents</a></i> 
&nbsp;</p>
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<a NAME="comp-opti"></a>Options
</font></font></font></b></td></tr></table>
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<p>
Options are processed in command line order. Any option you specify on
the command line remains in effect only for the image that follows.  All
options are reset to their default values after each image is read.
<p>
For a more detailed description of each option, see
Options, above.
<a href="GraphicsMagick.html"><em>GraphicsMagick(1)</em></a>.
<br>&nbsp;<br>
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<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-authenticate">-authenticate</a> <i>&lt;string&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>decrypt image with this password</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-auto-orient">-auto-orient</a>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>orient (rotate) image so it is upright</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-colorspace">-colorspace</a> <i>&lt;value&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>the type of colorspace</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-compress">-compress</a> <i>&lt;type&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>the type of image compression</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    -debug <i>&lt;events&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>enable debug printout</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-define">-define</a> <i>&lt;key&gt;</i>{<i>=&lt;value&gt;</i>}<i>,...</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>add coder/decoder specific options</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-density">-density</a> <i>&lt;width&gt;x&lt;height&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>horizontal and vertical resolution in pixels of the image</td></tr></table>
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<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-depth">-depth</a> <i>&lt;value&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>depth of the image</td></tr></table>
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<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-display">-display</a> <i>&lt;host:display[.screen]&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>specifies the X server to contact</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-endian">-endian</a> <i>&lt;type&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>specify endianness (MSB, LSB, or Native) of image</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-file">-file</a> <i>&lt;filename&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>write annotated difference image to file</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    -help
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>print usage instructions</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-highlight-color">-highlight-color</a> <i>&lt;color&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>pixel annotation color</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-highlight-style">-highlight-style</a> <i>&lt;style&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>pixel annotation style</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-interlace">-interlace</a> <i>&lt;type&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>the type of interlacing scheme</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-limit">-limit</a> <i>&lt;type&gt; &lt;value&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>Disk, File, Map, Memory, Pixels, Width, Height, Read, Threads, or Write resource limit</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-log">-log</a> <i>&lt;string&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>Specify format for debug log</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-matte">-matte</a>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>store matte channel if the image has one</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-maximum-error">-maximum-error</a> <i>&lt;limit&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>specifies the maximum amount of total image error</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    -metric <i>&lt;metric&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>comparison metric (MAE, MSE, PAE, PSNR, RMSE)</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    -monitor
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>show progress indication</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-sampling-factor">-sampling-factor</a> <i>&lt;horizontal_factor&gt;x&lt;vertical_factor&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>chroma subsampling factors</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-size">-size</a> <i>&lt;width&gt;x&lt;height&gt;</i>{<i>+offset</i>}<i></i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>width and height of the image</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-type">-type</a> <i>&lt;type&gt;</i>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>the image type</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-verbose">-verbose</a>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>print detailed information about the image</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-version">-version</a>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>print detailed GraphicsMagick version/build information</td></tr></table>
<table BORDER=0 WIDTH="94%">
<tr>
<td width="3%"><br></td> 
<td ALIGN=LEFT BGCOLOR="#FFFFFF">
<img SRC="images/right_triangle_option.png"
ALT=">" BORDER=0 height=14
width=15><b><font face="Helvetica, Arial"
><font color="#00B04F"><font size="+1">
    <a href="GraphicsMagick.html#details-version">-version</a>
</font></font></font></b></td></tr></table>
<table width="90%" border="0" cellspacing="0"              cellpadding="8">              <tr><td width="6%"><br></td><td>print compact GNU-style GraphicsMagick version information</td></tr></table>
<p>
For a more detailed description of each option, see
Options, above.
<a href="GraphicsMagick.html"><em>GraphicsMagick(1)</em></a>.
<br>&nbsp;<br>
</td></tr></table>
     <p>
<i><a href="#top">Back to Contents</a></i> 
&nbsp;</p>
